1. Field
The subject matter disclosed herein relates to synchronizing timing on a network.
2. Information
A network may include a type of optical network whereby multiple optical network terminals (ONT's) may be connected to a single optical line termination (OLT) via a network of one or more optical splitters and optical fiber, for example. One such optical network may include a passive optical network (PON), which does not comprise active components
Generally, a PON may include an OLT that may transmit a signal downstream to multiple ONT's, which may comprise end-users such as households and/or businesses on a network. Such an ONT may be configured, for example, to continuously receive downstream signals from the OLT while transmitting upstream signals during an allocated time slot. For example, individual ONT's may be assigned particular time slots during a network initialization and/or configuration. Using such time slots, upstream signals from multiple ONT's on the PON may be coordinated with one another to reduce collisions between the upstream signals, for example. Such an upstream signal from an ONT may include a request intended for an OLT, for example. Such requests may be cached by the requesting ONT while the ONT's time slot is not active.
Downstream signals from an OLT may include a semi-regular pattern of encoded digital ones and zeroes that may allow synchronization of internal clocks in multiple ONT's, which may all receive the same downstream signal. In some applications, however, such downstream signals may not include such a digital signal, but instead may include a format encoded as an analog signal, such as an analog video signal for example. In such applications, a downstream signal to multiple ONT's may not include a semi-regular digital pattern with which to synchronize internal clocks in the multiple ONT's. Accordingly, lacking a way to synchronize their internal clocks, ONT's may fail to accurately track their respective allocated time slot, leading to collisions among different upstream ONT requests.